Color photography



Sept. 22, 1942. H. P. MIXER 2,296,617

- COLOR PHOTOGRAPHY Filed Oct. 11, 1940 3 Sheets-Sheet 1 FIG. l. Q

- INVENTOR MlX R FIG 2 HAROL.D P E g L (JILL ATTORNEY Sept. 22, 1942.

H. P. MIXER coLoR PHOTOGRAPHY Filed 001:. 11, 1940 3 Sheets-Sheet 2 INVENTOR HAROLD F? MIXER @2 44 JIL ATTORNEY FIG.9

Sept. 22, 1942. H. P. MIXER 2,296,617

COLOR PHOTOGRAPHY Filed Oct. 11, 1940 3 Sheets-Sheet 3 47 B 3 5 4V7A 9 TU NGSTEN 6 DAYLIGHT iNVENTOR HAROLD R MIXER AT TORNEY Patented Sept. 22, 1942 UNITED STATES PATENT OFFICE COLOR PHOTOGRAPHY Harold P. Mixer, Rockville Centre, N. Y. Application October 11, 1940, Serial No. 360,700

8 Claims.

1 changing the light sensitive medium and the filter after each exposure. During this time, which'is considerable, the subject may move and also the necessaryoperations in changing filters and film often jars the camera, thereby resulting in poor negatives which do notregister.- It is also well known that certain filters have specific light characteristics of exposure which vary in a predetermined ratio, which must be maintained if a correct set of negatives is to be obtained. In other words, heretofore the art of color photography by the consecutive shot method has been a highly specialized procedure only possible with the best equipment and under perfect conditions.

It is, therefore, the principal object of this invention to provide a camera which will permit the making of separation negatives by the consecutive shot method almost instantaneously.

A further object is to provide a camera in which the color filters and film are changed mechanically during the making of the separation negatives.

A still further object is to provide a camera in which the filters may be easily changed to suit any type of lighting condition.

Another object is to provide shields for said filters which are calibrated in accordance with the light factor of each filter to insure correct balance of density between negatives.

Still another object is to provide a device which is adapted for use with any lens of any focal length providing it is color corrected.

A still further object is to provide a camera for making separation negatives by the consecutive shot method which is simple in operation,

easy to manufacture and efiicient in use.

The principal feature of the invention is the use of a rotating drum on the periphery of which is removably secured a plurality of interchangeable filters which are rotated by the drum bemittent film feed which is adapted to feed film only at a time when no filter is passing between the lens and film.

A still further feature is the use of interchangeable shields over the filters which have apertures therein of an area equal to the filter ratio of each filter.

Another feature is the spacing of the filters on the drum in such manner that sufiicient time is provided for feeding the film during the passage of a blind space in the drum.

A more clear conception of the operation, construction, and further objects of the invention may be had from the following specification when read in conjunction with the accompanying drawings, in which Fig. 1 is a side elevation of a camera with the invention attached;

Fig. 2 is a cross section taken along line 2.2 of Fig. 3, showing the drive mechanism;

Fig. 3 is a cross section taken along line 3-3 of Fig. 1;

Fig. 4 is a cross section taken along line 4-4 of Fig. 3 showing the location of the filters, shields, and film feed;

Fig. 5 is a. schematic development of the drum showing the spacing of the filters, the relative size of the apertures, in the shields and the necessary filters for photography in tungsten ligh Fig. 6 is similar to Fig. 5, the filters being shown with their corresponding shields for daylight photography;

Fig. 7 is a plan view of the film gate;

Fig. 8 is a front elevational view of Fig. '7 looking toward the lens; and

Fig. 9 is a detail cross section taken along line 99 of Fig. 4 showing the exposure counter.

The invention is disclosed in an attachment for an ordinary bellows type camera (Fig. 1), but it is obvious that the device may well be built in a camera with very little change of design.

The attachment comprises a box-like container l0 having an opening ll (Fig. 4) in one of the sides thereof, which is adapted to register with the open back of any well known type of camera 9. To facilitate the fastening of the attachment to a camera two rails II are provided which are adapted to slide in and engage a pair of offset lugs l4 secured to the back of the camera. This type of fastening is well known on certain film pack adapters for plate cameras.

The container [0 comprises a base portion i5 and a cover portion l 6 which is secured by screws I! to tapped members It secured to, or formed erated.

on, the sides of the base portion. The cover plate is provided with a, circular aperture l9 through which a handle 20 is adapted to extend. Pivotally mounted on the inner face of the cover is a latch member 2| formed as shown in Fig. 2. The latch member has a lug or button 22 formed thereon which extends through a slot 23 in the casing. The latch member 'is biased in a clockwise direction by a spring 24. Also plvotally mounted on the cover is a bell-crank 25 which acts as a stop member and is resiliently held in the position shown by the spring 26.

A sleeve 21 (Fig. 3) having a flange 28 formed on one end thereof is fastened to the base portion I in any well known manner, in the present instance by screws. Mounted in the sleeve 21 is a short shaft 30 which is formed with a flange 3| on one end thereof and is tapped at the other end to receive a screw 32 which retains the shaft30 in the sleeve 21. Secured to the flange 3| is a drum 35 of any suitable material, preferably a molded plastic, which is open at its unfastened end.

Positioned on the outer end of shaft 30 is a flanged hub 36 to which the handle 26 is secured by means of screws 38. The handle and sleeve are retained on the shaft 30 by a screw 4i fastened into the tapped end of the shaft.

The flanged hub 36 has a tooth 42 formed thereon which is adapted to be engaged by a pawl member 43 pivotally mounted on the drum the bell-crank 25. A stop pin 46 is secured in the drum 35 and so positioned that when the nose of the pawl is just clear of the periphery of the .tooth' 42, the pin 45 prevents further rotation thereof. The nose of the pawl is formed with a slight cam face to insure against engagement with the tooth 42 unless the pawl is positively op- When the latch 2| is rocked counter-clockwise by the depression of button 22, the pawl 43 is released and is rocked by spring 45 into contact with the flanged hub 36. Rotation of the handle 28 brings the tooth 42 into positive engagement with the pawl 43, which being pivotally mounted on the drum 35 causes it to be rotated. Near the end of a complete rotation or cycle of the drum the tail of the pawl engages the bellcrank 25 and rocks it counter-clockwise until the tail of the pawl snaps past after which the bell- 7 stop pin 46. In this position the tail of the pawl comes into end to end engagement with the bellcrank 25, thus preventing any counter-clockwise movement of the drum 35.

Secured to the periphery of the drum over definitely spaced apertures 41 are frames or holders 48 in which may be positioned filters 50 and calibrated shields 5|. The frames 48 are preferably made of spring metal riveted to the drum 35 at one edge and provided with notches 52 (Fig. 5) on the free edge. Pins 53 are secured in the drumwith which the notches 52 cooperate to hold theframes in place. The filters may having a twenty degree; opening.

be of any well known type preferably gelatin and the shields are formed as shown in Figs. 5 and 6, having openings of equal length but of various widths. The width of the openings is determined by the light factor of the filter with which the shield is used-and the ratio between the individual filter and the others in the group. The openings also vary as to factor rating of the type of film used. The following table illustrates the differences:

Shield Shield Filter daylight opening Tungsten opening The above table shows the filter factors for daylight and tungsten or artificial light together with the angular opening in degrees of the shields used therewith for two types of film-X and Y.

It will'be noted that the openings in the shields vary directly as the filter factor, 1. e., the filter having the highest factor having a shield with the greatest angular opening.

Using the above table, if it were desired to make negatives with film X by tungsten light, the blue filter would be positioned in the holder over the aperture 41 (Fig. 5) which is the first to pass between the lens and the film. Due-to the fact that this filter has a rated factor of ten for this type of film a shield' with a fifty degree opening (which is the maximum) will be placed over the filter. In the holder over aperture 41A a green filter will be placed together with a shield having a thirty degree opening due to the fact that the rating is six and in the last aperture 413 a red filteris used with a shield If the film to be used was the film Y the filters and shields would be the same except for the shield for the red filterwhich due to the fact that its rating is only one-half that of the other film would only have a ten degree opening. It will be noted that the shields (Fig. 6) for use in daylight work vary more widely, for instance, with film X the red filter uses the larger opening in the associated shield while with film Y the green filter uses the larger opening, i. e., forty-nine degrees. It is also to be noted that the shields with the red filter for both films vary as widely as possible, the film X using the maximum opening and the film Y using the minimum.

Rotation of the drum 35 brings the filters in succession between the lens of the camera and the film. In fact, the film is scanned by the filters during this rotation and, therefore, the film must be stationary. Due to this fact the film must be fed during the time a blank space between filters is passing the aperture Therefore, the apertures 41, 41A, and 41B are spaced unevenly about the periphery of the drum, thus. allowing time for the film to be fed. It will be noted that the tures 41 and 41A, but, due to the decreasing width of the shield openings, the film is not scanned until the film has come to rest. This design permits the use of a drum of smaller diameter than supply spool 88 which is pivotally mounted on a stub shaft having a flange 82 by which it is secured to the base portion I5. A pressure roller 53 is carried on a spring-pressed bell-crank 84 and acts as a brake on the supply roll. The film 58 passes through a film gate which will be described hereinafter and thence to a small drum 86 which is rotatably mounted on the sleeve 21. The drum 88 is provided with a slot 81 with which is associated a spring-pressed holding member 88. The film after being passed through the film ate is inserted into the slot 81 until the end is gripped by the holding member. The holding member is pivotally mounted by lugs I8, which extend beyond the side of the drum 66.

The film drum is driven by the outer drum 35 (Figs. 2 and 3) through the medium of a flange 1| secured to the inner surface near the closed end thereof. At predetermined spaced intervals on the fiange II are pins and slots I2 and I3. These pins and slots are adapted to cooperate with a star wheel I4 having alternate teeth I5 and pins I5. The star wheel has a long hub which is slotted at IT to engage lugs on a sleeve 18 having a flange thereon. The star wheel and sleeve I8 are mounted on a stud shaft 19 which is secured to the base portion I5. The wheel and sleeve are held on the shaft by a screw 88. Secured to the flange on sleeve I8 is a gear wheel 8| (Fig. 4), which meshes with a gear 82 riveted on a flanged hub 83 mounted on the sleeve 21. This gear has a pin 84, which engages a hole in the film drum 66.

As the outer drum 35 is rotated, one of the pins on flange 'II will engage a tooth I5 on the star wheel, thus rotating a pin I9 thereon into a slot I3, which, upon further rotation of the drum, will rotate the star wheel one-third of a revolution. Through the gears 8| and 92 the film drum 68 is rotated an angular distance sufficient to feed a frame of film, which is one-third of the full amount to be fed during a full rotation of the crank 28.

Film gate The film gate comprises a plate 98 formed as shown in Figs. 4, '7, and 8 in which is an opening 9| adapted to register with the opening II in the casing l8. The plate 98 is formed with wings 95 which guide the film. Secured to plate 98, but spaced a sufiicient distance therefrom to permit free movement of the film, is a plate 95. The plate 96 is bent at right angles to form a base 92 by which the film gate is secured to the base portion I5. The base 92 has. a pair of ears 93 thereon which form bearings for one end of a pair of rollers 94. Plate 96 is also formed with cars 91 in which the other ends of the rollers 94 are journaledp A small web 98 connects the wings 95 and the fiat portion of the plate 98 and overlies the rollers 94 to prevent the film from riding off the rollers. The plate 98 has no openings therein and forms a fiat table which guides and positions the film to be exposed within the focal plane of the camera lens.

Exposure counter closure has fifty-six teeth, is a gear I88, which has fifty teeth (Figs, 4 and 9). The gear I88 is secured to a hub I8| on whichis secured a dial I82 containing inserts I82 carrying the designations from one to four." The hub I8I is mounted on a stub shaft or stud I84 secured to the base portion I5. The hub and assembled gear and dial are spring-pressed into alignment with gear 8|. An aperture I85 in the casing I5 permits dial I82 to be read.

The gear 8| is rotated as described above three revolutions to one of the handle 28. Each time handle 28 is rotated, three frames of film are fed, which exposes the three negatives from one color photograph. Therefore, the ratio of fifty-six to fifty between gears 8| and I88 will bring a new digit into register with the apertures I85, indicating the exposure of a complete set of negatives for Meshing with gear 8 I, which in the present dis- 7 one color photograph.

When loading the camera the counter may be reset by raising gear I88 out of mesh with gear 8| against the tension of the spring and setting the dial. I

The correct exposure of the film in the present device is acquired by a little practice as the exposure is determined by the speed at which the handle 28 is rotated and the lens diaphragm opening. It is obvious that a spring motor or other type may well be substituted for the handle 28 without in any way altering the present invention. With a spring type motor a settable governor would insure a constant speed and the only determining factor for exposure would be the diaphragm setting,

The camera is loaded or the filters changed by removing the screws .II for the cover and the screw 32 for the shaft 38. This permits the cover and the drum 35 to be removed as a unit as the shaft 38 is free to be withdrawn from the sleeve 21 without affecting the film feeding and carrying mechanism. With the drum out of the casing the filters and shields are exposed and may be easily changed. The film spool 58 and drum may then be removed and new film placed thereon. The drum 6G is removed by removing the screw 88, which permits the removal of the star wheel 14, which, in turn, frees the drum. When the drum 35 is replaced in the casing, care must be exercised that the star wheel is correctly positioned, as shown in Fig. 2, so that the teeth and pins thereon will not interfere with the fiange I I.

While I have described and disclosed what I believe to be an operative structure, it is obvious that many changes in construction may be made therein without departing from the spirit of the invention.

What I claim as new, and desire to secure by Letters Patent, is:

1. In a camera of the type described, a lens, a rotatable drum having a plurality of filters mounted thereon adapted to be successively positioned in register with said lens, a film roll and a winding reel therefor mounted in said drum but not rotatable therewith, and a driving means for said reel actuated by said drum for feeding film when said filters are not in register with said lens.

2. In a camera of the type described, a lens, a rotatable drum having a plurality of filters mounted thereon adapted to be successively positioned in register with said lens, a film roll and a winding reel therefor mounted within said drum but not rotatable therewith, and driving means for said reel comprising a star wheel having alternate teeth and pins thereon, an annular ring secured to said drum having a plurality of pins and slots thereon located at predetermined positions for cooperation with said pins and teeth -on said wheel to rotate said wheel intermittently to feed said film a specified amount upon rotation of said drum at a time when said filters are not in register with said lens.

3. In a camera of the typedescribed, a lens, a film, a drum rotatable between said lens and film, three color filters removably secured in the periphery of said drum, a feeding means for said film positioned within said drum, said means being intermittently driven by said drum during the time no filter is passing between said lens and film and shields for said filters having apertures therein of diiferent area, said area varying in accordance with the light factor of the associated filter.

4. In a camera of the type described, a lens, a rotatable drum having a plurality of replaceable color filters of. varying characteristics mounted thereon in definite spaced relation, shields associated with said filters, said shields being formed with openings corresponding to the light factor of its associated filter, a film roller and a reel for said film mounted within said drum but not rotatable therewith a star wheel connected to said reel and rotatable by said drum for rotating said reel, and means for rotating said drum to cause an intermittent feeding of said film and a scanning of said film successively bysaid filters. In a camera of the type described, a lens, a film, a rotatable drum havinga plurality of filters thereon, a shield for each of said filters having an opening therein corresponding to the light factor of its associated filter and film and a feeding means for said film positioned within said drum, said feeding means being driven by said drum during the time no filter is passing between said lens and film.

6. In a camera of the type described, the combination of a lens, a drum having a plurality of filters interchangeably mounted on the periphery thereof, a film positioned within said drum, feeding means for said film intermittently driven by said drum-and means for rotating said drum to pass said filters between said film and lens at a time when said film is stationary.

'7. In a camera of the type described, a lens, a rotatable drum having a plurality of filters mounted thereon adapted to be successively positioned in register with said lens, a film roll and a winding reel therefor mounted in said drum, and a driving means actuated by said drum for feeding said film from said roll to said reel.

8. In a camera of the type described, a lens, a rotatable drum having a plurality of filters thereon, a shield for each of said filters having an opening therein corresponding to the light factor of its associated filter, a film positioned within said drum and means for-rotating said drum to successively feed said film and 'interpose said filters between said lens and film.

HAROLD P. m. 

